<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
</head>
<body>
<script src="vue.js"></script>
    <div id="app">
        <input type="text" v-model='mag'/>
        <h1>{{msg}}</h1>
    </div>
<script type="text/javascript">
    var vm=new Vue({
        el: '#app',
        data:{
            msg:'hello'
        }
    });
</script>
</body>
</html>